$ D = \left[\begin{array}{rrr}3 & 5 & 9 \\ 4 & 2 & 9\end{array}\right]$ What is $ D^{T}$ ?
To find the transpose, swap the rows and columns. $ D^{T}$ = $\left[\begin{array}{rr}3 & 4 \\ 5 & 2 \\ 9 & 9\end{array}\right]$